Temperature measuring device



Nov. 12, 1946. H. vo HORTENAU 2,411,120

TEMPERATURE MEASURING DEVICE Filed Sept. 6, 1944 @Mma;%

Patented Nov. 1-2, 1946 2,411,120 TEMPERATURE MEASURING DEVICE Hans vonHortenaii, Stockholm, Sweden, to Stlg K. M. Billman, Stockholm,

assignor Sweden Application September 6 1944,'Serial No. 552,879 InSweden October 19, 1943 2 Claims. (Cl. 201-63) The present inventionrelates to a temperature measuring device and particularly to means formeasuring the temperature of a, fluid passing through a conduit, forinstance for measuring the temperature of the water in a hot watersystem in connection with the measuring of the'heat quantity consumed inthe system, said heat quantity being constituted by the product of thequantity of water flowing therethrough and the drop of the watertemperatures in the system. In known measuring devices for measuring thetemperature of a fluid passing through a conduit, such as mercurythermometers, liquid thermometers, gas thermometer-s, steam pressuredistance thermometers,- thermo-couples or resistance thermometers ofknown constructions, 'dimculties are encountered due to the fact thatthese measuring devices interfere with the flow of the fluid through theconduit and result in hydraulic losses and faulty measurements onaccount of heat emission through the metallic parts of the thermometers.

The invention has for its. object to avoid the above namedinconveniences and to provide a temperature measuring device which inspite of simple construction renders possible very accurate measurementsof the temperature without interfering with the flow of the fluid andwithout faultymeasurements due to heat emission.

I attain this object by the device illustrated in the accompanyingdrawing showing a central section of the device.

Between two portions of a conduit, not shown, for the fluid thetemperature of which is to be i measured, there is inserted a casingwhich in accordance with the embodiment illustrated consists of atubular body, 2 having a connecting flange I for one portion oi'theconduit. Said body 2-.is suitably secured to a plate 3 constituting aconnecting flange for the other portion of the conduit. A packing plateI is inserted between the parts 2 and -3. The members indicated have thesame inner diameter D as the conduit. An annular measuring member 4 isarranged within the casing in a manner such that the inner wall 5 of themember 4. constitutes part of the conduit and has the same innerdiameter as the same.

Between the casing and the outer wall 6 and the 7 end walls I, 8 of themeasuring member, there is arranged a layer 8 of a'suitable heatinsulating material, such as cork, Bakelite or the like. The. measuringmember 4 i connected to a tube ll having a low heat conductivity andextending through the casing and the insulating layer 9. Through thetube H, electrical conductors may be connected with the measuringmember.

The walls of the measuring member are as thin as possible and consist ofa material, such as copper, having a great heat conductivity, in orderalways to maintain the measuring member at the same temperature as theliquid or gaseous fluid passing through the conduit. Since the measuringmember, except the contacting surface with the fluid, is on all sidessurrounded by the heat insulating layer, very accurate measuring resultswill be obtained. Due to the fact that both the casing and theinsulating layer as well as the measuring member have the same innerdiameters as the conduit proper, hydraulic losses during the passage ofthe fluid through the measuring means will be entirely avoided.

The measuring member is filled with a material the specific electricresistance of which is responsive to variations of temperature. Forinstance, the measuring member may be filled with a resistance coil incase of direct current, or, in case of alternating current, withelectrolytes of a liquid or semi-liquid (jelly-like) consistency,

coal substances or crystalline resistances, a resistance coil 12 beingpartly and diagrammatically indicated in the drawing.

It will be understood that the invention is not limited to theembodiment shown and described by way of example.

What I claim is:

1. A temperature measuring device adapted to be inserted in a fluidconduit and comprising a casing constituting part 01' said conduit, anannular measuring member located in said casing and including a materialthe speciflc electric resistance of which is responsive to variations oftemperature, the diameter of the inner cylindrical race of saidmeasuring member being substantially equal to the inner diameter of saidconduit,

and heat insulating means disposed between said casing and the outercylindrical face of said measuring member.

2. In a temperature measuring device, a straight tubular passage for aliquid to be measured, a tubular resistor element forming part of saipassage and having a resistance varying with its temperature, the innercylindrical surface of said element having substantially the samecrosssection as the inner surface of the rest of the tubular passage andbeing located flush therewith, and a thermally insulating layersurrounding the resistor element to prevent heat conduction therefrom inan outward radial direction.

HANS von HoR'rENAti.

